Wire-drawing die



. Patented Apr. vL12, 1927.

UNITED STATES insrlsNT OFFICE.A

FREDERICK voLLMEn, or cRNF'onD, NEW. JERSEY.

y l WIRE-DRAWING- DIE.

Applica/noa ined January 16,1926. serial 1ro. 81,676.

adequate amount of .reinforcement to the diamond, and the strain on the diamond produced by drawing the wire through its perforation, which is largely an outward ressure or bursting strain, is borne mostly y the 'diamond itself, and the strength of the diamond being insufficient to -withstand this strain, eventuall the diamond breaks, usually splitting i two parts and then breaking into. smaller fragments. Also commonly, under the pulling strain of the wire, vdiamonds become slightly loose in their settings and then the diamond will soon break. In order to reduce the breakage, commonlyA heretofore larger' diamonds have 'been' used than otherwise would be necessary for drawing wires of' given sizes,

` these diamonds, to obtain the greatest strength for a given size, usually being of oblate orflatte'ned shape. The high price of such large diamonds ofl good quality is prohibitive, hence the diamonds commonly usedhave many flaws and defects, which causethem to wear more rapidly; also when these imperfect diamonds are rebored for drawing wire of a larger size, a flaw is likely to be encountered which renders the diamond worthless. .Various kinds of settings have been employed, but, with a somewhat extensive knowledge of the dies in use, I do not know of any which are free from the above noted objections'. l v An object of the invention is to prevent the breakinglof the wire-drawing member, 0 and especially to prevent the breaking of a wire-drawing diamond 'in a diamond die. AOther objects of the invention are to enable the .use of smaller diamonds, diamonds of 'I globular shape, and more nearly perfect dia-l j 45. monds, which wear much longer'and which.

may be rebored without developing defects. Another object is to provide. a permanent `reinforcement for the diamond which* will revent the possibility-of the'diamond ever ecoming loose in the die. Thus a general' object of the invention is to produce a betterl die than heretofore has been made and at a less cost of production.

According to this invention, the wirewill now be described with reference to the drawingmember, moreparticularly a wires drawing diamond, is provided with a reinforcement which ytakes the wire-drawing strain. More particularly, in -carrying out the invention, the originally rough diamond 1s provided with a smooth conical] tapered eri-pherall surface, and the rein orcementor .the diamond comprises a metal block having therein a smooth, round conically tapering hole of the same taper as the taper on the diamond and in which the diamond 05 is tightly gripped at its smooth periphery.

Th1s reinforcing block may be asmall cylindrical block or nib -and the metal of which it 1s composed should be suiciently hard andhave sulicient tensile strength to provide the desired reinforcement. By making the gripping or inward pressure of this blockor nib on the diamond fully as great or greater than the radial or outward pressure of the wire being drawn" through the hole in the diamond, this outward .pressure lor strain will be borne entirely by the nib and not by the diamond. Also, because of the taper, thepull of the wire on the diamond tends to keep the diamond -tightvin its reinforcement and to make lit even tighter, so that the diamond cannot become loose under the Wire-drawing strain.

The accompanying drawings show a wirel drawing diamold'die constituting one ema5 bodiment of the inventlon, and also illustrate a process or method involved in carry# ing out the invention, the drawings'being made to an enlarged scale.y The invention, which is pointed out in theapp'ended claims,

drawings, in which:

' Fig'l is a, plan`view of a blank formed' by casting metal around a rough diamond.

Fig. 2 is an axially central section on the line 2-2 of Fig. 1 with the diamond` in elevationf.

Fig. 3 is an elevation'or side view, and

Fig. 4 is a; central vertical sectiqn of av headed conically tapering plugl formed by turning down the blank shown in Figs. 1

and2to form a conical taper on the metal.-

and on the diamond, thelower end of the plug havin-g been openedto expose the diam01di f y lF'g. 5 is a plan.. vi ew ofa metallic reinforcing block for the diamond having therein a round conically tapering 'hole of the same taper as the plug but of slightly less diameter at corresponding points along their length.

Fig. 6 is an axially central section on.the line 6 6 of Fig. 5.

Fig. 7 is a similar section with the plug in elevation and dropped into the hole in the block approximately as far as it will freely enter when the block is heated.

Fig.l 8 is a similar view Withthe plug forced into the hole in the block as far as its head will let it go, so that the block tightly grips the diamond at all points on its smoothed periphery..

Fig. 9 is a similar view and is an axially central section on the line 9-9 of Fig. 10, showing the plug with its headremoved and as opened at its upper end to expose the diamond, the metal parts of the plug being Shown in section and the diamond in elevation.`

Fig. 10 is a'plan View of Fig. 9.

Fi 11 isa central axial sectionsimila'r to Fig. 9, showing the diamond reinforcing block or nib as centrally set in a metallic cup or casing by means of a suitable metallic filling which surrounds and covers the nib.

Fig. 12 is a similar view with the filling removed at the top and the metal of the casing removed at the bottom to provide central flaring openings exposing the diamond.l

Fig. 13 is a view similar to Fig. 12 and is. a central axial section ofthe completed die, and shows the Wire-drawing perforation which has been provided in the' diamond. i

Fig. 14 is a partial horizontal section on the line 1.4--14 of-Fig. 13.

Fig 15 is a partial plan view of Fig. 13.

The manner of carrying out the invention a's illustrated in the drawings to produce the Wire-drawing diamond die shown in Figs. 13, 14 and 15 as an embodiment of the invention will now be described.

By means of a suitable moldv (not shown) a metal envelope 1 is cast around a rough diamond 2 of globular'shape so as'entirelyv to cover the diamond orbury it therein thereby to form the cylindrical blank shown in Figs. 1 and 2, in which the center of the diamond is located on the axis of the cylindrical blank but nearer to the bottom than to the top of the blank.

The diamond 2 is not shown as having a wire-drawing. hole or perforation therein, however, so far-as the present invention is concerned the diamond could have such perforation formed therein before it is cast into -the metal envelope 1. So far as this invention is concerned it is immaterial at what stage the diamond is perforated 'in the `manufacture of the die.

Any one of a large variety ofy metals, or alloys, may .be employed to form the' metallic envelope 1'. For example,l brass may be used; or a harder met-al, provided its temperature when in a molten condition is not so high asto'be harmful to' the diamond; and molten metal produced from' the mixture Well known as thermit is suit-able for the purpose, as suoli' metal, whenV it has solidified and cooled, strongly adheres to the diamon'd.

The diamond-containing blank is n'oW fixed at its upper end (as viewed in Fig. 2) i in a chuck on a lathe, and,1 by means lof a suitable tool, a small flaring opening 3 (Figs.

3, 4 et seq.) is made in the metal at the center .o'f the'free end `of the blank, to expose the diamond, thereby to makesure that the diamond is centered in the blank and also more readily to determine if thechucking is true; and the opening v3,-being a necessityin the completed die, may -as well be made at this stage.

-By 'means of an ordinary suitabletool,

theprojeeting portion of the blank is now turned down along tapering lines until the diamond 2 is reached, after which a dia-l mond-pointed tool is used to turn down both the diamond and the metal to form the coni-- cally tapering headed plug shown in Figs.'

3 and 4. This plug has a head or iange 4 (which was held in the lathe chuck)v and a gradually and' smoothly conically tapering shank or stem which comprises (as viewed in Figs.3 and 4) an upper metal part 5, a

lower metal partv 6 and a middle part formed by the diamond 2, which has formed thereon Ya smooth annular conically tapering ino lperipheral girdle 7, the smooth surface of which-forms a continuously smooth taper with the smooth surfaces of the tapering metallic end parts 5 and 6. The unsmoothed or rough portions of the diamond 2a are embedded in the metalend parts and 6, which 'firmly adhere thereto. The diameter of thej conically tapering plug may vary, depend- 'ng upon the, size of thediamond, and because diamonds of diffe-rent sizes are employed according to the size of wire to be drawn throughthe die. l

Occasionally the rough diamond may have such an uneven surface that a depression orv cavity therein will leave -at some point a small bridge of metal connecting the end parts 'and 6 ofthe plug, the metal then fillin the cavity or depressionin the diamon but in most instances a Icomplete smogth `annular surface is formed on the periphery of the diamond.

A metallic 'reinforcement is now formed for the tapered diamond. First a disc-like cylindrical -blank (not shown) may be 'formed in any suitable Way, for example it may be cast, or it may be cut and shaped from a piece of metal, and this original .blank mayor .may not havea hole through its center. When it has no hole it has been found convenient first 'to bore a small hole that is, six degrees for metrical points, has proved satlsfactoryp-andthrough the blank axially thereof By means of a suitable tapering boring tool the originalaperture is now enlarged and given a tapering form, thereby to produce the nib vor reinfdrcing block 8 shown in Figs. 5

and 6 et seq., which has through its vcenter a round conically taperin hle 9. This hole 9 ismade to fit the tapering plug, the taper of the plug and the hole being made the same and the size of the hole beingl made such that the plug will have a tight-fit therein. The hole 9 is made of slightly less. diameter than the plug at corresponding points, for example, the top of the hole is of less diameter than the upper end of the upper metal'part 5 of the plug, i. e., adja-` cent the lower surfaceof its head 4, and a difference in diameter which 'has .proved that is approximately the drawings.

The diamond-reinforcing block or nib the taper shown in 4is now moderately heated in any convenientstantial aid in centering the nib. To secure.-

\ way, for example, by means of an ordinary blow torch, to expand vthe nib and'slightly enlarge' the hole 49. The conically tapering plug is`now dropped into the expanded conically tapering hole 9 vin the lhot -nib 8, which 'it-will freely enter about to the extent shown in Fig. 7. The conically. t-apering plug, of which the 4peripherally smoothed diamond 28L forms a part, is n ow gradually forced int-o the heated nib to the l desired extent by means vof a suitable press,

so that the plug and particularly'the'diamond 2a at all points on its smooth peripheral taper 7 is tightly wedged in the tapering aperture 9. Theahead o r flange 4 on'the plug has been found to form a convenient gauge for correctly limitingthe extent to which the taperin plug, and therefore the tapered diamond, s iould be inserted into the tapering hole 9 in ,the nib, as is shown in FigQS. The heated nib is ;now permitted'` to cool, sothat it shrinks upon and grips4 the diamond 2a firmly smooth conical taper 7. l

The head 4 on the-plug has now served at all points on its -its doublepurpose as a means for chucking and as a means for limiting the extent to which the diamond is'wedged into the nib,

hole`9, and henceforth would only be objectionable. Accordingly, the head 4 is now cut oil" flush with the upper surface of lthe nib 8, andat the same time, if desired, the

top ofthe nib may be dressed down. A.

.small flaring opening-10 is now'made in the upper metal' part 5 at the center thereof,

l down to the diamond 2, as shown in Figs. 9 and 10. It is tobe no'ted that`tbe lower metal end part-6 does not extend all of the way through the nib, a srnall 4space lbeing left between its lower end and the lower face of` the nib, the purpose of which will'- hereinafter appear. As shown in Figs. 9 and 10 the nibpart of the die vis nowl complete with the, as yet,

unperforated diamond -2a gripped thereinto be reinforced 'thereby in the completed die. The small size of the nib ring 8, that shown in theA drawings being abbut one-half inch in diameter and about onefourth `ofan incli thick, requires thatthe nib, be set In .The diamond-carrying nib shown in Figs.

9 and-10 'is now centered in the casing l11,

sal

the upper central opening 10 being -of sub- I' the nib inthe casing 11` a'suitable metallic filling 12 is placed in the casing around and covering the nib, as shown in Fig. 11.'. This filling 12 may be a hard soldersuch as brass solder: V f As shown in Fig. 12, aliaring entrance opening -13 is formed in the filler 12 down to the diamond, the" filling metal being removed from the opening 10 in the Vupper metal part '5 of the plug, anda similar flaring exit opening' -14 1s made in the bottom of' the cup 11, thereby completingk the casing structure. The onlyw thing remaining to be done to complete vthe die is to provide -a w-ire drawing perforation in the diamond 2a, assumin and as is'shown viu the drawirrgs, that 't e diamondhas not been previouslyV perforated, which, as hereinbefore mentioned, could as well be the case.

In the completed die shown'in Figs. 13,

14 and 15 the diamond has had a hole 15"y drilled through it and this hole has been shaped and polished, thereby to produce the perforated wire-drawing diamond 2". The present invention is not concernedfwithy the shape of the wire-drawing hole through the diamond, and the shape of 'theperforationl 15 shown in the drawings maybe considered as conventional. Also it is not necessary that the erforation or drilling ofthe diamondsha l be thelastthingl done,'and the invention has been carried out by beginn-ing with a -perforateddiamoni but more care is then required inv orderl to have'fthelwiredrawing hole truein lthe A completed die.

VIt is necessary that ythe metal or alloy of Cil which the reinforcement 8 is composed shall be sufficiently hard to hold the diamond securely, as if it were too soft it would yield to such an extent under the wire-drawing strain that the diamond would not be adequately reinforced. Also this reinforcement 8 should have sufficient tensile strength that it will not break under the wirerawing strain transmitted or transferred to it by the wire-drawing diamond 2l. There are a number of suitable metals and alloys which may be used to form the diamond-reinforcing block or nib ring 8, and a metal or alloy of any kindxthat answers the requirements may be used. For example, steel maybe used. Another example is a copper alloy well known as Monel metal. l

= The casing 11 is not essential to the carrying out of the present invention and, if so desired, may be omitted by making vthe diamond-reinforcing nib 8 of larger external diameter, and also somewhat thicker so as to have a suitable entrance' opening. The hereinbefore described shrinking of the hard and strong metallic reinforcing block upon the diamond after the latter has 'been tightly wedged therein yresults in the perforated wire-drawing diamond 2b being strongly gripped with an inward pressure at all points on its smooth peripheral surface and 'thus securely and permanently reinforced against breakage under the wire- `drawing strain. It has been found in carrying out the invention that the 'inward pressure of the reinforcement 8 upon the diamond 2b yis lgreater than the outward pressure in its'perforation l5 due to the drawing of the wire so that the perforated wire-drawing diamond 2* is subjected only to opposed compression strains and there is no bursting strain upon itand a margin of safety against the diamond splitting under the wire-drawing strain is thus provided.k This has been proved in tests by, in one-instance splitting the diamond into two parts and in another instance into four parts longitudinally through its perforation, and when the parts `of these purposely broken .diamonds were 'assembled andreinforced in a die according to the present invention, the dies withstood the test of drawing wire the same as if the `diamonds had been whole.

The ulling strain of the wireV being drawn t rough the diamond has a tendency not only to keep the smoothly tapered diamond 2F tight but yto make it tighter in its taperingly apertured reinforcement 8.

While movement of the diamond toward the back of thedie, if such movement takes place, is imperceptible, yet the diamond is free thus to move should the pulling strain 0f the wire be sufficiently great. The slight `*space provided between the end of the metal plug part 6 and the Irear face of the nib 8 provides 'for such movement without obtrudid not break. In extensive and severe tests and in actual practice incommercial wiredrawing use, no .diamond has yet broken when reinforced according to the presentinvention, although for a given size of wirea smaller diamond is employed than in any other dies in use, so far as l am aware.

While all of the features ofthe invention have distinct utility in combination, it is to be understood that some of these features might be modified or even omitted from the combination and advantageous results still be obtained. It is obvious that various modifications may be made in the construction illustrated in the drawings and above particularly described, within'the principle and scope of the invention as defined in the appended claims.

I cla-im: l i 1. A diamond die for drawing wire having, in combination, a perforated wiredrawing diamond provided with a smooth taper on its periphery, and a block of hard` and strong metal having therein a tapering hole which fits the taperl on. the diamond and into which the tapered diamond has been wedged to reinforce the diamond.

2. A diamond die for drawing wireliaving, in combination, a perforated wiredrawing diamond provided with a smooth taper on its periphery, and a block of hard and strong metal provided with a tapering hole to fit the taper on the diamond and shrunk upon the diamond at Vits taper to reinforce the diamond.

3. A diamond die for drawing wire having, in combination, a perforated wiredrawing diamond provided on its periphery with a smooth conical taper, and a block of hard and strong metal provided with a conically tapered hole which fits the conical taper on the diamond and in which the diamond has been wedged at its conical taper to reinforce the diamond.

4. A diamond die for drawing wire having, in combination, a perforated wiredrawingdiamond provided on its periphery ywith a smooth conical taper, and a block of hard and strong metal provided with. a conically tapered hole which fits the forcing block of suitably hard and strong metal provided with a hole for the plug and in which the diamond tightly fits at its smooth periphery, whereby the block grips the diamond and reinforces it.

6. A diamond die for drawing Wire having, in combination, a diamond-reinforcing block of suitably hard and strong metal having therein a conically tapering hole, and a longitudinally apeirtured conically tapering plug tightly fitted in said hole, said plug comprising a middle part consisting of a perforated Wire-drawing diamond which is peripherally conically tapered,

5 and apertured metal end parts having a peripheral conical taper substantially flush with the taper on the diamond whereby, the block grips the diamond and reinforces it.

7 A Wire-drawing die comprising, in combination, an apertured wire-drawing stone having a smooth circumferential substantially circular surface band in a plane at right angles to the axis of the aperture, and a metal block having a hole therein with a wall corresponding tothe said band and tightly gripping the stone about said band.

In testimony whereof Iaix my signature.

FREDERICK VOLLMER. 

